A multicentre interventional study to assess blood-borne viral infections in Belgian prisons.

BACKGROUND: Prevalence data on viral hepatitis B (HBV), hepatitis C (HCV), and HIV infection in prison are often scarce or outdated. There is currently no systematic screening for these blood-borne viral infections (BBV) in Belgian prisons. There is an urgency to assess the prevalence of these BBV to inform policymakers and public healthcare. METHODS: This was a multicentre, interventional study to assess the prevalence of BBV using opt-in screening in prisons across Belgium, April 2019 - March 2020. Prisoners were tested using a finger prick and BBV risk factors were assessed using a questionnaire. A generalized linear mixed model was used to investigate the association between the various risk factors and HCV. RESULTS: In total, 886 prisoners from 11 Belgian prisons were screened. Study uptake ranged from 16.9 to 35.4% in long-term facilities. The prevalence of HCV antibodies (Ab), hepatitis B surface antigen (Ag) and HIV Ab/Ag was 5.0% (44/886), 0.8% (7/886), and 0.2% (2/886). The adjusted odds for HCV Ab were highest in prisoners who ever injected (p < 0.001; AOR 24.6 CI 95% (5.5-215.2). The prevalence of detectable HCV RNA in the total cohort was 2.1% (19/886). Thirteen (68.4%) prisoners were redirected for follow-up of their HCV infection. CONCLUSIONS: Opt-in testing for viral hepatitis B, C and HIV was relatively well-accepted in prisons. Compared with the general population, prisoners have a higher prevalence of infection with BBV, especially for HCV. Systematic screening for these BBV should be recommended in all prisons, preferably using opt-out to optimize screening uptake. TRIAL REGISTRATION: Retrospectively registered at clinical trials NCT04366492 April 29, 2020.

Low hepatitis C prevalence in Belgium: implications for treatment reimbursement and scale up.

BACKGROUND: Prevalence data of chronic hepatitis C virus (HCV) infection are needed to estimate the budgetary impact of reimbursement of direct-acting antivirals (DAAs). In Belgium, the restricted reimbursement criteria are mainly guided by regional seroprevalence estimates of 0.87% from 1993 to 1994. In this first Belgian nationwide HCV prevalence study, we set out to update the seroprevalence and prevalence of chronic HCV infection estimates in the Belgian general population in order to guide decisions on DAA reimbursement. METHODS: Residual sera were collected through clinical laboratories. We collected data on age, sex and district. HCV antibody status was determined with ELISA and confirmed with a line-immunoassay (LIA). In specimens with undetermined or positive LIA result, HCV viral load was measured. Specimens were classified seronegative, seropositive with resolved infection, indicative of chronic infection and with undetermined HCV status according to the test outcomes. Results were standardized for age, sex and population per district, and adjusted for clustered sampling. RESULTS: In total 3209 specimens, collected by 28 laboratories, were tested. HCV seropositivity in the Belgian general population was estimated to be 0.22% (95% CI: 0.09-0.54%), and prevalence of chronic HCV infection 0.12% (95% CI: 0.03-0.41). In individuals of 20 years and older, these estimates were 0.26% (95% CI: 0.10-0.64%) and 0.13% (95% CI: 0.04-0.43), respectively. Of the total estimated number of HCV seropositive individuals in Belgium, 66% were between 50 and 69 years old. CONCLUSIONS: Prevalence of HCV seropositivity and chronic infection in the Belgian general population were low and comparable to many surrounding countries. These adjusted prevalences can help estimate the cost of reimbursement of DAAs and invite Belgian policy makers to accelerate the scaling up of reimbursement, giving all chronically infected HCV patients a more timely access to treatment.

Distribution of HCV genotypes in Belgium from 2008 to 2015.

BACKGROUND: The knowledge of circulating HCV genotypes and subtypes in a country is crucial to guide antiviral therapy and to understand local epidemiology. Studies investigating circulating HCV genotypes and their trends have been conducted in Belgium. However they are outdated, lack nationwide representativeness or were not conducted in the general population. METHODS: In order to determine the distribution of different circulating HCV genotypes in Belgium, we conducted a multicentre study with all the 19 Belgian laboratories performing reimbursed HCV genotyping assays. Available genotype and subtype data were collected for the period from 2008 till 2015. Furthermore, a limited number of other variables were collected: some demographic characteristics from the patients and the laboratory technique used for the determination of the HCV genotype. RESULTS: For the study period, 11,033 unique records collected by the participating laboratories were used for further investigation. HCV genotype 1 was the most prevalent (53.6%) genotype in Belgium, with G1a and G1b representing 19.7% and 31.6%, respectively. Genotype 3 was the next most prevalent (22.0%). Further, genotype 4, 2, and 5 were responsible for respectively 16.1%, 6.2%, and 1.9% of HCV infections. Genotype 6 and 7 comprise the remaining <1%. Throughout the years, a stable distribution was observed for most genotypes. Only for genotype 5, a decrease as a function of the year of analysis was observed, with respectively 3.6% for 2008, 2.3% for 2009 and 1.6% for the remaining years. The overall M:F ratio was 1.59 and was mainly driven by the high M:F ratio of 3.03 for patients infected with genotype 3. Patients infected with genotype 3 are also younger (mean age 41.7 years) than patients infected with other genotypes (mean age above 50 years for all genotypes). The patients for whom a genotyping assay was performed in 2008 were younger than those from 2015. Geographical distribution demonstrates that an important number of genotyped HCV patients live outside the Belgian metropolitan cities. CONCLUSION: This national monitoring study allowed a clear and objective view of the circulating HCV genotypes in Belgium and will help health authorities in the establishment of cost effectiveness determinations before implementation of new treatment strategies. This baseline characterization of the circulating genotypes is indispensable for a continuous surveillance, especially for the investigation of the possible impact of migration from endemic regions and prior to the increasing use of highly potent direct-acting antiviral (DAA) agents.

Assessing the sensitivity and representativeness of the Belgian Sentinel Network of Laboratories using test reimbursement data.

BACKGROUND: The Belgian Sentinel Network of Laboratories (SNL) was created in 1983 in order to monitor trends in infectious diseases. Given the evolution of the surveillance system, such as the waivers, fusions and adhesions of laboratories over time, it is important to evaluate whether the SNL is still fit for purpose. This study aims to evaluate aspects of the sensitivity and representativeness of the SNL by means of a test coverage analysis. METHODS: We estimated test coverage of the SNL using the ratio of reimbursed tests performed by participating laboratories to the total number of tests performed between 2007 and 2012, for 12 (groups of) pathogens. We further evaluated the geographical difference coverage of the SNL at regional and provincial levels. RESULTS: We found that test coverage of the SNL was stable over time and close to, or greater than, 50 % for the 12 (groups of) pathogens studied. These results hold for the three regions of Belgium but not for all provinces. We showed that some provinces had a low test coverage for some pathogens and that test coverage was more variable over time at provincial level. CONCLUSIONS: This sensitivity and representativeness study based on test coverage suggests that the SNL is capable to describe trend and to monitor changes in the 12 (groups of) pathogens studied both at national and regional levels. Therefore, the SNL is useful to contribute to estimate the burden of disease and to inform preventive measures. It should however be reinforced to allow to be used as an alert system at provincial level.

Surveillance of Infectious Diseases by the Sentinel Laboratory Network in Belgium: 30 Years of Continuous Improvement.

In 1983 the sentinel laboratory network was established because of the need to describe the epidemiological evolution of infectious diseases. During the study period of 30 years (1983-2013), microbiology laboratories reported on weekly basis the laboratory diagnosed cases for a selection of infectious diseases. This resulted in a large longitudinal laboratory based database allowing to provide trends over time and distribution by person and place. During this period, adaptations to data collection were made due to changes in diagnostic methods and public health priorities, introduction and application of digital revolution, and multiple reorganizations of the laboratories. Since the surveillance network is dynamic, it necessitates a continuous evaluation to ensure that, over time, it continues to be representative of the general epidemiological trends in the country. Secondly the aim is to examine the robustness and stability of this surveillance system. Here we demonstrated that the flexibility of the data collection methodology by the sentinel laboratory network is unique and that adaptations do not affect the capacity of the system to follow trends. Therefore, the surveillance by this network is representative of the current epidemiological situation in Belgium. To our knowledge, no such surveillance network with such a long-term follow-up and demonstrated stability for multiple infectious diseases in the general population was earlier described. Furthermore, expected trends due to the implementation of vaccination or other events were accurately detected. The collected data obtained from this network allows interesting comparisons with other national and international information sources.

Establishment and reinforcement of the national reference centers for human microbiology in Belgium.

BACKGROUND: Microbiology reference laboratories are critical in the development of high-quality clinical and public health services. In Belgium, the reference laboratories performed their activities on a voluntary basis and lacked a legal status. METHODS: Pathogens or groups of pathogens necessitating a national reference center (NRC) were prioritized based on diagnostic and epidemiologic relevance. Terms of reference for each of these pathogens were developed. RESULTS: Recently, 40 NRCs for different pathogens or groups of pathogens have been installed in Belgium to fulfill the following core functions: offering reference diagnostics, collecting reference materials, sharing information and scientific advice, participating in national and international networks, collaborating with research workgroups, and contributing to surveillance activities. CONCLUSIONS: These NRCs are important focal points of the national and international network in public health microbiology.

Simple Algorithm for Identification of Bordetella pertussis Pertactin Gene Variants.

Studies performed in several countries have demonstrated the recent emergence and subsequent dominance of circulating Bordetella pertussis strains harboring pertactin and pertussis toxin variants not included in pertussis vaccines. Determination of the pertactin gene variants is commonly performed using a time-consuming and expensive sequence analysis. We developed a simple and reliable pertactin typing algorithm suitable for large-scale screening. The assay correctly identified all pertactin alleles in representative strains. The typing of 231 clinical strains of B. pertussis routinely isolated in Belgium showed that this algorithm was adequate to identify less-frequent prn types like prn9 and prn11.

Prevalence of fragilysin gene in Bacteroides fragilis isolates from blood and other extraintestinal samples.

Of 166 Bacteroides fragilis isolates, 26.2% of 103 isolates from blood and 20.6% of 63 extraintestinal isolates harbored the fragilysin gene (difference not statistically significant). Clinical characteristics and evolution were comparable in patients with B. fragilis bacteremia with or without this enterotoxin. Fragilysin seems not to be an important virulence factor in B. fragilis disease.

Molecular typing of Bordetella pertussis isolates recovered from Belgian children and their household members.

Recently, a moderate increase in the prevalence of pertussis, possibly contracted from adults, has been observed among unvaccinated children. During a 3-year period, we prospectively enrolled 93 index patients with a polymerase chain reaction (PCR) and/or culture result positive for Bordetella pertussis. Among 63 household contacts of 28 index patients, PCR and culture for B. pertussis identified 25 B. pertussis-positive persons. Nineteen of 25 B. pertussis-positive household contacts were asymptomatic. Isolates were available from 10 families of both index patients and household contacts for molecular typing by pulsed-field gel electrophoresis (PFGE) and for genotyping of pertactin and pertussis toxin by sequence-specific PCR and sequencing. PFGE demonstrated homogeneity among the isolates recovered from within each family but heterogeneity among the isolates recovered from different families. B. pertussis isolates recovered from index patients and their household contacts were indistinguishable by molecular typing, demonstrating that identical strains can cause full pertussis disease in children and asymptomatic infection in adults and adolescents.